Question

Is there such a thing as an ethical reason for unauthorized access into a computer system?

Answer 1

Of course there is. On a simple level, consider a parent trying to locate their missing child. Someone might break into their social media accounts to see if there are messages that might help determine their whereabouts.

Consider a website hosting inappropriate pictures of children. Breaking into the server hosting the files and removing them is 100% ethical. 

I'm sure you can think of more examples.